In order to effectively do reengineering a (workflow or business) process model as a lifecycle-managing activity, it is important to secure an elaborate process mining system that is able to discover the enacted process model from an enactment event log dataset of a corresponding process model. In evaluating the process mining approaches and systems, there are two fundamental research issues; One is the discovery accuracy issue and the other is the discovery adequacy issue. The former is about the syntactical quality of the discovered process model, while the later is about the semantical quality of the discovered process model. In this paper, we initiate an innovative process mining approach, which is named as the explainable process mining approach, as a silver bullet that can be a decisive solution for both of the research issues at the same time. We also validate its practical feasibility through an operational experiment on an exemplary dataset available from the 4TU Center for Research Data. Ultimately, through the explainable process mining approach and system, it ought to be possible for the modelers and the mining engineers to effectively explain the reasons why the structural formations of control-flow gateway-activities of the discovered process models are shaped as well as stemmed from in terms of fulfilling the process reengineering works in the process lifecycle management activities.